iTunes is a free application for Mac and PC. It plays all your digital music and video. It syncs content to your iPod, iPhone, and Apple TV. And it's an entertainment superstore that stays open 24/7.

Organize your music into playlists
Edit file information
Record compact discs
Copy files to an iPod or other digital audio player
Purchase music and videos on the Internet through the built-in iTunes store
Run a visualizer to display graphical effects in time to the music
Encode music into a number of different audio formats.